On Feb 27, 2007, at 8:26 AM, Stan Stockton wrote:
> Wind about 6 turns of coax tightly on a 4" UV resistant PVC pipe
> which will be good for 20/15/10.
Electrically, this is a very effective balun. I had planned to do
this when installing my A3S. In fact, I even figured out a method to
mount the 4" PVC to the boom by cutting at 45 degrees and then using
a U-bolt to hang the balun underneath.
In the end, I opted for a different solution. I had purchased some
ferrite beads with a 5/8" I.D. and about 1.25" long at a hamfest at a
bargain price. I measured one of these with an MFJ-259. A simple
calculation showed that about 15" of these beads would give adequate
balancing impedance from 7-28 MHz.
These beads are slid on the coax before connecting to the antenna. I
used 14 gauge THHN solid wire to wire tie the coax below the boom.
Makes a tidy and effective balun.
Bill Coleman, AA4LR, PP-ASEL Mail: email@example.com
Quote: "Not within a thousand years will man ever fly!"
-- Wilbur Wright, 1901
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